With a government shutdown looming larger and their party divided over any dealmaking, House Republicans have a new, shiny object: Budget Committee Chairman’s Paul Ryan’s 2012 budget.

Ryan will roll out a blueprint Tuesday that could slash up to $6 trillion in the next 10 years from spending, reforms and cuts entitlements, and overhauls sections of the tax code. Never mind that Ryan’s ambitious vision has no chance of passing the Democratic Senate — the 2012 budget is likely to provide Republicans with a measure of unity they’ve been lacking as they try to wrap up work on the stalled 2011 spending plan.

It’s a high-stakes moment for Ryan’s political career: He has been touted as a conservative visionary and budget wizard but yet faced serious internal Republican pressures over his proposals.

The Republican budget is expected to include several major proposals: reduction of the corporate tax rate to 25 percent; elimination of corporate tax loopholes; spending cuts with enforceable caps; reforms to “save critical health and retirement programs”; health reform that “repeals and defunds the president’s health care law”; and a promise to restore “America’s exceptional promise,” according to GOP aides, lawmakers and a draft summary of the budget.

Sources said Ryan plans to lower spending below 2008 levels, a dramatic cutback. There was discussion about lowering to 2006 levels, but that won’t make it into the budget. Those huge cuts were suggested in January by Republican Study Committee Chairman Jim Jordan (R-Ohio) but received little support at the time.

Other plans include block grants for Medicaid, a proposal that many governors of both parties prefer, as it shifts control to the states. Those on Medicare would get to choose among competing private insurance plans — which advocates have described as “premium support.” The budget is also expected to kill funding for the health care law, likely by stopping the expansion of Medicaid and subsidies for private health insurance.

“The president’s budget was a safe budget, this budget is not a safe budget,” said Rep. James Lankford (R-Okla.), a freshman member of the Budget Committee, told POLITICO. “It’s not safe politically, but it’s the right thing to do.”

But in a sign of the pushback Ryan will receive, former Comptroller General David Walker is quick to point out the shortfalls in the plan.

“Chairman Ryan ought to be encouraged for laying out a budget with more deficit reduction” than the $4 trillion, 10-year cuts that the Simpson-Bowles commission proposed last December, Walker said.

But Walker, who has become a leading deficit hawk, lamented that Ryan’s budget will not raise additional revenues and apparently will have few, if any, Pentagon cuts. “I don’t believe that it’s politically feasible without putting those on the table.”

Congress will not have to wait long to act on the proposal. The plan, according to lawmakers and aides, is to keep the forward momentum by moving the proposal quickly through the House before it stalls at the Senate doors.

The bill will likely get marked up in committee Wednesday, and the Rules Committee plans to outline the parameters for debate on Tuesday or Wednesday of next week. At that point, the House is expected to pass the resolution and send it to the Senate.

Tuesday’s rollout represents a re-emergence, of sorts, for Ryan, who delivered the GOP rebuttal to President Barack Obama’s State of the Union message in late January but has been in retreat from the main stage in national politics while Congress has focused on mopping up spending bills for fiscal 2011.

Republicans have not forgotten the peril of internal divisions as they propose an ambitious budget aimed at unifying the GOP.

For many years, Ryan has been the political third rail. Democrats made him a campaign issue, positioning him as the embodiment of a conservative who would privatize Social Security and dismantle Medicaid. His budget plans were battered by Democrats during last fall’s campaign. But as he has pointed out, the GOP’s 63-seat House gain showed that the Democrats’ objections gained little traction at the time. Further, many freshmen have embraced his broad strategy.

Ryan’s so-called “road map” document for budget planning, which all but abolished Medicare and Medicaid, was held at arm’s length by Republicans, including House Speaker John Boehner (R-Ohio). Although Boehner has given Ryan wide latitude in drafting next year’s budget plan, the Budget Committee chairman still needs to show that he can garner 218 votes.

And most recently, Ryan was the public face of a major flub from House Republican leadership: the miscalculation that roughly $30 billion in cuts would be enough for Republicans in their first whack at fiscal 2011 spending bills. Republicans quickly doubled Ryan’s figure, making it look as though he’d been meek in his offering, although it was a leadership-backed plan.

Recognizing the fragile political calculus, House Republicans have sought outside help. In two meetings, most recently on Friday, GOP aides have mulled the budget messaging with top pollsters. In meetings at the Republican National Committee headquarters, the aides huddled with the likes of GOP pollsters Dave Winston, a close Boehner ally, Dave Sackett of the Tarrance Group, Glen Bolger of Public Opinion Strategies, Whit Ayres and Linda DiVall.

Republicans have also carefully choreographed the Ryan rollout. Ryan went on “Fox News Sunday” to begin to frame the discussion as his party is “saving” Medicare and Medicaid. To explain the details, Ryan went to The Wall Street Journal’s opinion pages with a Tuesday op-ed.

Although many Republicans remain wary of Ryan, he receives strong encouragement from conservatives such as The Weekly Standard publisher Bill Kristol, who repeated this weekend his embrace of Ryan as the GOP’s ideal 2012 presidential nominee. House Republican leadership will hold a news conference with Ryan on Tuesday morning.

Lawmakers involved with the crafting of the bill describe a deliberate, painstaking process.

“He’s a worker,” said Rep. Jason Chaffetz (R-Utah), a sophomore who sits on Ryan’s panel. “He’s been the staff; he’s now leading. So he’s a hands-on manager of this. He understands it better than anybody else in the room. So he commands the respect to have the discussion that needs to be had. I’d like to think that each of the members has their fingerprints on it, but Ryan is certainly the leader of the process.”

“On the CR, I’ve got this degree of frustration, but the budget, I really like,” Chaffetz told POLITICO.

Lankford, who has little experience in politics, has not been involved with the continuing resolution negotiations. But he said Ryan appears to be handling budget negotiations a bit differently than leadership has handled the stopgap spending debate.

“Behind closed doors, when we process things, there hasn’t been some magic number hanging out there, saying we have to get to this,” Lankford said. “It’s been a focus on ‘how do we get moving, how do we start this process, how do we get back to balance and pay off debt.’”